How To Prune Leyland Cypress

If you have a row of Leyland cypress trees acting as a screen, you know they grow fast. Learning how to prune Leyland cypress is the key to keeping them healthy and looking good. Without the right trimming, these popular evergreens can quickly become overgrown, thin at the bottom, or even damaged by heavy snow. This guide gives you expert techniques to prune them correctly, ensuring they stay dense and beautiful for years.

Pruning isn’t just about cutting branches. For Leyland cypress, it’s a preventive health measure. The goal is to guide their natural growth, not fight it. When you use the right techniques, you encourage thick foliage and a strong structure that resists damage.

Why Pruning is Non-Negotiable

Leyland cypress can grow three feet or more each year. If left alone, they outgrow their space fast. Proper pruning solves several common problems:

Prevents Overcrowding: They need good air circulation to avoid fungal diseases.
Maintains Shape: Keeps that classic, neat conical or columnar form.
Promotes Density: Regular light trimming encourages branching, filling in thin spots.
Reduces Stress: Removing dead or damaged wood helps the tree focus energy on healthy growth.

The Golden Rule: Never Cut Into Old Wood

This is the most critical tip. Leyland cypress will not reliably sprout new growth from branches that have been cut back to leafless, brown wood. Always make your cuts in the green, needled foliage. If you cut to far back, you’ll be left with a permanent brown patch.

Best Time of Year to Prune

Timing is everything for a healthy trim. The ideal window is in late winter or early spring, just before new growth begins. You can also do a light trim in late summer, but avoid fall. Pruning in autumn can encourage tender new growth that will be killed by the first frost.

Late Winter/Early Spring (Primary Prune): This is the best time for any significant shaping.
Mid-Summer (Maintenance Trim): A light cleanup to neaten up new growth is fine.
Times to Avoid: Late fall and very hot, dry periods in midsummer.

Essential Tools for the Job

Using sharp, clean tools makes the job easier and healthier for the tree. Dull tools crush stems, inviting disease.

Hand Pruners (Bypass): For small branches under ½ inch thick.
Hedge Shears (Manual or Electric): For shaping and trimming the green foliage. Electric shears save time on large hedges.
Loppers: For thicker branches, up to about 1.5 inches.
Pruning Saw: For any rare, larger cuts.
Disinfectant: Wipe blades with rubbing alcohol between trees to prevent spreading disease.

Step-by-Step Pruning Technique

Follow these steps for a successful pruning session. Always start with less—you can always cut more later.

Inspect the Tree: Walk around it. Identify dead, diseased, or broken branches first. Look for areas that are thinner or sticking out awkwardly.
Remove Problem Branches: Using your pruners or loppers, cut dead or damaged branches back to their point of origin or to a healthy side branch. Make clean cuts.
Shape the Tree: Using your hedge shears, start trimming the current year’s growth. Aim to maintain a shape that is slightly narrower at the top than the bottom. This allows sunlight to reach the lower branches, preventing them from dying back.
The Tapered Cut Method: Don’t shear straight up and down. Instead, make sweeping, slightly angled cuts following the tree’s natural taper. This looks more natural and is better for the tree.
Step Back Frequently: After a few cuts, step back and look at the overall shape. This prevents you from over-pruning one area.
Clean Up Debris: Rake up and remove all cuttings from around the base of the tree to discourage pests and mold.

Avoiding Common Pruning Mistakes

Even with good intentions, its easy to make errors. Here are the big ones to avoid.

Topping the Tree: Lopping off the top to reduce height is a disaster. It destroys the tree’s form and leads to weak, ugly regrowth.
Shearing into a Tight Box: This creates a dense outer shell that blocks light and air from the interior, causing inner branches to die.
Pruning Too Late in the Season: As mentioned, this risks frost damage on new growth.
Ignoring the Bottom: Letting the top grow wider than the bottom shades out lower limbs, leading to that common “leggy” look.

How to Rejuvenate an Overgrown Leyland Cypress

If you’ve inherited a monster, don’t despair. While you can’t drastically reduce its size, you can improve it over a few seasons.

Year 1: In early spring, thin out the tree by selectively removing some entire branches back to the trunk. This opens up the interior for light and air. Do not reduce the overall height or width by more than a quarter.
Year 2: Focus on shaping the new growth that responds. Continue to thin any crowded areas.
Year 3: By now, the tree should be filling in nicely. Resume regular, light maintenance pruning to guide it.

Patience is key here. A severe, one-time chop will likely leave you with a permanently damaged tree.

Aftercare: What to Do Post-Pruning

A little care after pruning helps your trees recover quickly.

Watering: Give the trees a good, deep watering if the weather is dry. This reduces stress.
Mulching: Apply a 2-3 inch layer of organic mulch around the base (not touching the trunk) to conserve moisture.
Fertilizing: Avoid heavy fertilizing right after a big prune. A light application of a balanced, slow-release fertilizer in spring is usually sufficient.

FAQ: Your Leyland Cypress Pruning Questions Answered

How often should you trim Leyland cypress trees?

For a maintained hedge, plan on pruning once or twice a year. The main trim should be in early spring, with a possible light tidy-up in mid-summer if needed.

Can you cut the top off a Leyland cypress?

It is not recommended. Cutting off the central leader (topping) ruins the tree’s natural shape and forces out weak, multiple leaders that are prone to splitting. To control height, you can very lightly tip-prune the new growth each year, but never cut into old wood.

What happens if you don’t prune Leyland cypress?

They will grow very tall and wide, often becoming misshapen. The lower branches may die from lack of light, leaving you with a tall, bare trunk and a heavy top that can split in wind or snow.

Why are the inside branches of my Leyland cypress turning brown?

This is often due to lack of sunlight or poor air circulation caused by improper shearing. It can also be a sign of fungal disease like Seiridium canker, especially if you see scattered die-back on outer branches too. Ensure your pruning technique allows light inside.

How much can you cut back a Leyland cypress?

In a single season, never remove more than one-third of the total green foliage. For overgrown trees, stick to an even more conservative approach, removing only about a quarter of the live growth per year over several years.

Pruning your Leyland cypress might seem daunting at first, but with the right timing and techniques, it becomes a simple garden task. Remember the golden rule: always cut within the green, needled growth. By following these expert tips, you’ll keep your trees healthy, dense, and perfectly proportioned, ensuring they remain a beautiful asset to your landscape for a long time to come.